EXTRACT (Extract Data Table) › When to Use › Extracting in Native Key Sequence

Extracting in Native Key Sequence

When not using Simplify or MUF is not enabled, an extract of a table in Native Key sequence without MULTUSE=YES requires that the database not be open for update by any copy of CA Datacom/DB. This protection helps ensure the successful retrieval of the data. Multiple EXTRACTs may be executing at once with the same or different tables in the database. However, if two or more are executing within a single area, the completion of the first updates the Directory (CXX) to remove the fact that the area is being unloaded, which loses protection for any remaining EXTRACTs for an area. Therefore, to help ensure protection, only one table in an area should be done at one time.

An extract with MULTUSE=YES requires that the database be set in the MUF startup without ACCESS NOOPT. The database is opened for update during the EXTRACT, and that update protects the area containing the table to ensure a successful retrieval of the data.

Note: With MULTUSE=YES, only one EXTRACT or BACKUP may be executing at one time within a single data area.

When using Native Key sequence you can do a parallel extract. See Parallel Extract.